Hitherto, it has been known to utilize an interlayer restraining effect (or interlayer effect) as a means for improving the color reproducibility of a color photographic material. Referring to the example of a color negative photographic material, impartation of a development restraining effect from the green-sensitive layer to the red-sensitive layer decreases coloration of the red-sensitive layer by white light exposure as compared to coloration of the red-sensitive layer by red light exposure. Since the gradation of a color negative paper system is balanced so that exposure of the paper with a white light reproduces a gray color on the color print, the above-mentioned interlayer effect causes cyan coloration of a higher density by red light exposure on the print than by gray light exposure and, as a result, red reproduction of a higher saturation degree is possible on the print with restraining cyan coloration thereon. In the same way, the development restraining effect from the red-sensitive layer to the green-sensitive layer in the color photographic material provides green reproduction of a higher saturation degree.
One known means of elevating the interlayer effect is a method of using iodide ions to be released from silver halide emulsions during development. Specifically, in a photographic material to be processed by this method, the silver iodide content in the interlayer effect donor layer is elevated and that in the receptor layer is lowered. Another method of elevating the interlayer effect is illustrated in JP-A-50-2537 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), in which a coupler capable of releasing a development inhibitor by reaction with an oxidation product of a paraphenylenediamine developing agent in a color developer is added to an interlayer effect donor layer. Still another method of elevating the interlayer effect is a so-called automatic masking method in which a colored coupler is added to a colorless coupler so as to mask any unnecessary absorption of the colored dye from the colorless coupler. In accordance with the method of using such a colored coupler, the amount of the colored coupler to be added may be increased to cause more masking than the masking of the unnecessary absorption of colored dye from the colorless coupler to thereby yield the same effect as the intended interlayer effect.
Where the saturation (chroma) of the primary colors of red, green and blue is elevated by these methods, there occurs a drawback that the yellowish to cyanic green color hue can not be reproduced faithfully. In view of this situation, JP-A-61-34541 has proposed a technique of overcoming this drawback. Specifically, JP-A-61-34541 has proposed a color photographic material having at least one blue-sensitive silver halide emulsion layer containing yellow-coloring color coupler(s), at least one green-sensitive silver halide emulsion layer containing magenta-coloring color coupler(s), and at least one red-sensitive silver halide emulsion layer containing cyan-coloring color coupler(s) on a support, in which the center-of-gravity sensitivity wavelength (center-of-gravity .lambda.G) of the spectral sensitivity distribution of the green-sensitive layer satisfies 520 nm&lt;center-of-gravity .lambda.G&lt;580 nm, and at least one red-sensitive silver halide emulsion layer satisfies both (a) 500 nm&lt;center-of-gravity .lambda.R&lt;560 nm and (b) center-of-gravity .lambda.G-center-of-gravity .lambda.R&gt;5 nm where the center-of-gravity .lambda.R is a center-of-gravity wavelength of the distribution of the degree of interlayer effect to be imparted to the red-sensitive layer from other layers in a wavelength range of from 500 nm to 600 nm. The proposed silver halide color photographic material gives a sharp color image with faithful color reproduction.
In the proposed technique, it is preferred that the layer capable of imparting an interlayer effect to the red-sensitive layer be a magenta-coloring layer in order to prevent the layer capable of imparting an interlayer effect to the red-sensitive layer from imparting the effect additionally to the green-sensitive layer and to inhibit any unfavorable influence on the color reproduction of the material.
However, where the proposed photographic material was used for taking a picture of a person and a color print was obtained from the exposed material, it was found that the graininess was too high in the area of the skin of persons in the print. The reasons for this were analyzed and it was determined that the graininess of the magenta coloration of the silver halide emulsion layer capable of imparting an interlayer effect to the red-sensitive layer was worse than that of the other coloring layers.
The reason why the graininess of the layer capable of imparting an interlayer effect to the red-sensitive layer was worse than that of the other silver halide emulsion layers is because the sensitizing dyes which have heretofore been added to the silver halide emulsion layer to which an interlayer effect is to be imparted had a lower color sensitizing efficiency because their absorption (the center-of-gravity wavelength: 500 nm/center-of-gravity .lambda.R&lt;560 nm) was weak so that the sensitivity/graininess ratio was not satisfactory.
Therefore, sensitizing dyes capable of giving a strong absorption (color sensitivity) in the center-of-gravity wavelength range of from 500 to 560 nm (preferably from 520 to 540 nm for sufficient color reproduction) have been desired in the art.